2.3 Earthquake Hazards and Safety

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Vocabulary

Liquefaction: Liquefaction occurs when the earthquakes severe shaking turns loose, soft soil into liquid mud suddenly.
Aftershock:An earthquake that occurs after another stronger earthquake had occurred in the same area.
Tsunamis: Large waves that form when a strong earthquake displaces the water creating large waves that are called tsunamis.
Base-isolated building: A building that is designed to rest on rubber pads or springs and reduce the damage produced by the earthquake.

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Outline

How Earthquakes cause Damage

• There are three types of damages which occur during an earthquake
  • Liquefaction
    • Liquefaction causes soil to turn into mud
    • During the 1964 earthquake, a whole housing development was swept into the sea because liquefaction caused a landslide that made the housing development slide down the cliff and into the sea.
  • Aftershock
    • Buildings that are damaged can be destroyed by an aftershock.
    • An aftershock is an earthquake that occurs after another stronger earthquake that occurred in the same area.
    • These aftershocks can strike hours, days, or even months later.
  • Tsunami
    • Sometimes when an earthquake strikes underwater, one of the plate rises above the other and the earthquake can trigger a tsunami.
    • Tsunamis are large waves that form when a strong earthquake displaces the water creating large waves that are called tsunamis.
    • The wave is very large but on open ocean the water only rises half-a-meter.
    • As they near land, they grow as tall as a six story building.

Making Buildings Safer

• To reduce the damage made by earthquakes, buildings must be made stronger and more flexible as the earthquake produces severe damage.
  • Also, older buildings need to be modified so that they can withstand stronger quakes.
    • To make buildings safer, you need to choose a good choice of location and also good construction methods.
• Choice of Location
  • The location of a building affects the type of damage it might have to face.
    • Earthquakes that occur on filled land can shake it very violently.
    • The farther away you live from a fault, the less damage there will be.
• Construction Methods
  • A base isolated building reduces the shock you get from an earthquake
  • A fixed base building is fixed to the ground so the energy released durinq an earthquake can destroy the building
  • The damage from most earthquakes is not caused by the shaking, but the ruptured water and the gas lines are the cause.

Protecting Yourself During An Earthquake

• In an earthquake, the main danger is falling items and broken glass
• If you are outdoors when an earthquake strikes, quickly move to an open area
• An earthquake kit for such emergencies should contain:
  • canned food
  • water
  • first aid supplies
  • flash lights
  • batteries
  • radio
  • clothes